An investigation has been made of the chemical properties of glasses in which the increasing amount of lime has been replaced by the increasing amount of ferric oxide or by ferrous oxalate.
The sample used for the tests is the glass powder of 20 to 30 mesh screen size (Tylor Standard Sieve).
The investigation of the solubility in water requires the treatment of 5g powdered sample in 100c.c. distilled water contained in a flask, immersed in the boiling water for one hour and the measurement of the amount of alkali liberated from the glass into the water.
The testing method of solubility in hydrochloric acid, sodium carbonate, and sodium hydrox iderespectively requires a treatment of 5g powdered sampl ein a basket of platiuum gauge immersed respectively in 20.24% HCl. 2N⋅Na₂CO₃, and 2N⋅NaOH each being contained in a flask kept in a boiling water bath for one hour and the measurement of the loss of the weight.
The solubility in water shows a marked decrease in the glasses, in which a small amount of lime has been replaced by a small amount of iron oxide, and no appreciable decrease is seen in the glasses containing a larger amount of iron oxide.
The results shows:- That in hydrochloric acid does not seen to depend upon the content of iron oxide. That in sodium carbonate solution presents a certain decrease till the definite value. That in caustic soda solution gives the minimum point at the glass, in which 2% of lime is replaced by 2% of iron oxide.
It is concluded that all these results have no dependence upon the state of oxidation of the iron oxide in the glasses.

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Experiments have been made on the influences of water content of bodies composed of dead-burned magnesite upon the condition of the bodies in mixing and shaping, that of test-pieces on shaping, physical properties of green test-pieces after one week, and also upon the properties of fired test-pieces. For these experiments, the clinker was ground to obtain 3 coarse grains which were from 3 to 2mm., from 2 to 1mm., and from 1 to 0.34mm. large; the equiproportional mixture of these 3 coarse grains was called coarse grain and batches were composed of its 80 to 0 parts and 20 to 100 pt. of fine powder which was prepared by pulverizing the coarse grain; bodies were made by adding 6 to 24 pt. of a solution of magnesium sulphate whose sq. gr. was 1.15 to 100 pt. of the batch. The test-pieces were hand-molded or pressed with a pressure of 300kg. per sq. cm. and were fired to cone 20 in a gas-fired kiln. The fired specimens have been examinod for compressive strength, modulus of elasticity (E), modulus of rupture (M), porosity, bulk density, etc., and the resistance for thermal shock has been calculated from their data. The results may be abridged as follows:
(1) If the bodies for hand-molding contain adequate amounts of the solution, the coarse grains are uniformly coated or bound by the fine powder on shaping and on firing. With its excessive amounts, the distribution of the fine powder and solution is not uniform, spaces between the coarse grains being filled with the fine powder; bubbles and cracks are liable to be produced in the spaces on firing.
(2) At adequate amounts of the solution, modulus of elasticity of the fired wares is low and the ratio of modulus of rupture to modulus of elasticity, M/E, reaches its maximum value.
(3) The less the proportion of the fine powder, the more the variation of E and M/E due to small changes of the amount of the solution.
(4) The effect of the amount of the solution is reduced with an increase of shaping pressure. Accordingly enough attention has to be paid for the amount in the hand-moulding.
(5) Compressive strength of unfired and fired wares shaped with rather excessive amounts of the solution is higher than that of those shaped with appropriate amounts of the solution. In many cases certain insufficient amounts of the solution give highest strength.
(6) Excessive amounts of the solution produce a slip of the fine powder and are apt to cause bubbling and cracking.

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As a preparatory study on the theory of the hardening of mixed portland cement, experiments have been made on the wet reaction between “white earths” or volcanic ashes and slaked lime by the aid of optical observation, X-ray analysis, thermal analysis, and the determination of free lime. 2 “white earths” and 3 volcanic ashes, both raw and calcined for 2hr. at 800°C., have been employed. Among them, “white earth” of Beppu contained 12.20% of insoluble matter and 78.45 and 2.16% of soluble silica and soluble alumina resp., while volcanic ash of Karatsu had 28.82, 25.68, and 13.42% of insoluble matter, soluble silica and soluble alumina resp. The results of the experiments may be condensed as follows:
(1) On the addition of water, calcium hydroxide is first adsorbed on the surface of minute grains of the stuffs and then reacts slowly with them, producing hydrates in gelstate.
(2) The mixing stuffs rich in soluble constituents and especially those containing much soluble alumina react actively. Thus the reaction of the Karatsu volcanic ash is most remarkable.
(3) The stuffs calcined at 800°C. are more active than the natural ones.
(4) The chemical reactions in the system calcium hydroxide-mixing stuff-water can be observed by a microscope at their early periods. However the reactions in later periods must be computed also by thermal analysis and the determination of free lime.

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